Diffused aeration systems are employed for injecting air or other gases such as oxygen into bodies of water; waste water and other liquids. These systems generally include a series of piping components with fittings and swivel joints, connected to a header system to which is connected a series of air diffusers, such as those of the membrane type shown in U.S. Pat. Nos. 3,525,436, 4,631,134 and 4,764,314. In service the header system, diffusers and part of the piping are submerged in the water, waste water or process liquid. Pressurized air or other gas is introduced in such a manner that biological or other processes are optimally satisfied. U.S. Pat. Nos. 4,294,696 and 3,396,950 show typical aeration systems. Heretofore, when the system is to be maintained the liquid has been withdrawn from the tank or vessel and work done on the system while the system is disposed in the tank. This has several drawbacks due to the inconvenience and hazard of working in the tank and the necessity of shutting down the liquid flow. Further the lower part of aeration system may well be covered with sludge which must be washed off before commencing repairs, rework or replacement of diffusers. Because of these problems others have practiced the use of various methods of lifting the aeration piping, including the diffusers, from the tank utilizing complex booms such as jib cranes or linear actuator-type hydraulic lifting mechanisms.
Such lifting equipments are normally relatively complex, expensive, large in size and difficult or impossible to position, especially on a walkway or small service platform extending at the edge or across a tank. A need has thus existed for a simple, maneuverable, small and easily maintained and operated device for servicing and maintaining or stowing a diffused aeration piping array and other piping arrays. Such a device would function to lift the operational part of the piping array from the tank to an out-of-the liquid position where personnel may easily access the array for required maintenance and servicing. A typical diffused aeration piping array utilizes 12 cm diameter drop pipes made of steel with a typical array of 20 diffusers. The piping may extend downwardly from about 3 M (meters) to about 6 M and have a total weight of about 200 kilograms which must be lifted. The lifting devices in the prior art have thus been of heavy duty, of large size and weight to take up the lift reaction forces.